Automatically-controlled self-lowering jack



J. CLKOPF.

AUTOMATICALLY CONTROLLED SELF LOWERING JACK.

APPLICATION FILED AUG.6, 1920.

1,392,066. I Patentedsepu 27,1921.

4 SHEETS-SHEET INVENTO g (7 2 ATTORNEY J. C. KOPF.

AUTOMATICALLY CONTROLLED SELF LOWERING JACK.

' APPLICATION man AUG.6, 1920.

1,392,066; e ept. 27,1921.

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INVEN 0R.

XLC/ A .I. C. KOPF.

AUTOMATICALLY CONTROLLED SELF LOWERING JACK.

APPLICATION FILED AUG-6, 1920.

PatentedSept. 27,1921.

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- v NVENTOR. m I. v I v c/ ATTORNE J. c. KOPF.

AUTOMATICALLY CONTROLLED SELF LOWERING JACK.

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25 BY W ATTORNEY UNITED STATES PATENT OFFICE-1.

JOHN o. KOIPEOF B LLEVUE, PENNSYLVANIA, AssIGNoR ro THE nUFn'MANUFAc- TUBING COMPANY, or PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

AUTOMATICALLY-CONTROLLED SELF-LOWERING JACK.

Specification of Letters Patent.

Patented Sept. 27, 1921-.

Application filed August 6, 1920. Serial No. 401,705.

T 0 all whom it may concern:

Be it known that I, JOHN C. Korr', a

citizen of the United States, and resident of the borough of Bellevue', in the county of Allegheny and State of Pennsylvania, ave invented a new and useful Automatically- Controlled Self-Lowering Jack, of which the following is a specification. Theinventionrelates t0 jacks, and more particularly to self-lowering screw-jacks; and the object is to provide a jack and jack mechanism of this character possessing advantages in respect to simplicity and suitability of construction, economy of manufacture, and-safety and convenience of operation. c I

In the accompanying drawings, illustrating the preferred embodiment of the invention:

Figure 1 is a vertical section through a jack embodying the invention;

Fig. 2 is a vertical section on the line 2-2 of Fig. 1, on a larger scale; and

Figs. 3, 4 and 5 are fragmentary horizontal sections on a still larger scale, taken on the lines 3-3, 4-4 and 5-5, respectively, of Fig. 2.

The jack shown in these drawings will now be described, it being understood that various changes may be made.

The mechanism is inclosed in a shell or frame 1, having an expanded supporting base 2, a hollow standard 3 rising therefrom, and an annex 4 adjacent the base. The base proper and the standard are made of separate sections united by bolts 5, and the annex or the outer portion thereof is also a separate section secured to the standard section by bolts 6.

A hollow cylindrical ram 7, constituting the jacking member, is slidably guided in a 7 bearing 8 in the top of the standard, a

key 9 in this bearing cooperating with a longitudinal groove 10 in the ram to keep the latter from turning The ram is elevated and permitted to descend by a screw 11 rotatably supported on the base by, a ball bearing 12, and extending upward within the ram, through a nut 13 in its lower end. This screw is of sufiiciently steep or quick pitch, so that the lifting mechanism will run down under the action of the load. It is actuated by a horizontal lifting shaft 14 journaled in a bearing 15 in the annex, and

shaft is journaled in a vertical position in bearings 21, 22 in the top and bottom of the annex, the worm being secured on its lower portion, and the wormand shaft being capable of slight vertical or end movement, the direction of end-thrust under load being upward.

An intermediate portion of the shaft 20 passes through a shelf or abutment 23 in the annex, at opposite sides of which are two multiple friction disk devices 24: and 25. The lower device 24 is a friction lock subject to the end-thrust of the worm, for preventing undesired descent, while permitting lifting; and manual means are provided in connection therewith for releasing and restoring the look, so as to start and stop the lowering. i f v In the particular construction shown, the device 24: comprises a pile of disks 26,- 27 which are engaged alternately with longitudinal ribs 28 on the shaft and ribs 29 on the interior of a barrel 30. A band-brake 31 encircling this drum is adapted to hold the sameand the disks 27 absolutely stationary in respect to rotation,' and is operable by a screw 32 and a handle 33 on the outside of the annex. The end pressure of the worm is applied to the disks by a thrust; collar 34 on the shaft above the worm, and is sustained by an end bearing boss 35 on the under side of the shelf 23, the barrel 30 having a back 36 which is adapted to bear against this boss.

When the manual brake 31 is relaxed the two sets of'disks 26, 27, and the barrel, are free to turn with the shaft, allowingthe loaded jacking member to move in a downward direction, which movement is arrested by again applying the brake. The stopping effected in this manner is cushioned because of the ability of the plane surfaces of the disks to slip briefly as the result of momentum, such slippage being overcome directly and surely by theend-thrust pressure, which is always proportional to the load. Owing to the nature of the clutch, the frictional locking action is also proportional; consequently the multiple surfaces afford holding area for comparatively heavy and comparatively light loads alike, and the excess friction is a constant, which, for any load, overcomes the inertia of the moving mass progressively, when the lock is restored by manual action. The cushioning effect is the more prolonged, the freer the descent and the more sudden the application of the brake, and is less in case of slow lowering, or can be superseded by careful manual control of the brake, but will always be developed in event of a condition of lowering which would endanger themechanism, the load or the operator. This load-actuated and manually-released and -restored lock, constituting an element in combination of the present jack, is' disclosed in my prior Patent No. 1,321,456, dated November 11 1919, reissued November 23, 1920, No. 14,991, and a modified form thereof, in which the restraining set of disks is permanently anchored'against rotation, and the lock manually released by separating the disks, or removing the end-thrust pressure, has been disclosed in another application, filed July 28, 1920, Serial No. 399,468.

The second multiple disk device 25 rests on a bearing boss 37 on top of the shelf 23, in a cup 38 formed thereon, and comprises alternating disks 39, 40, of which the disks 39 are engaged with longitudinal ribs 41 on the shaft 20, while the others are free from the shaft and engaged with ribs 42 of the cup. The disks of this device are unaffected by the upward end-thrust of the worm, as the shaft slides freely within them in its limited longitudinal movement. Downward pressure on the pile, that is to say, pressure exerted in a direction opposite to the endthrust pressure which actuates the friction lock 24, is exerted by the cam noses 43 of the arms 44 of centrifugal governor balls 45, said arms being connected, by a spring 46, and pivoted to a hub, 47, which is fastened to the upper part of the shaft. Thus, an automatic multiple-disk speed-controlled brake is afforded, to preventunsafe lowering. The governor being movable endwise with the shaft, sufficient space is normally provided beween the cam noses and the thrust collar 48 to prevent the brake from dragging.

The jack is operated manually to lift in the ordinary manner. During the lifting strokes the lock 24 is ineffective to oppose the lifting, because the action on the worm is reversed and the pressure is consequently removed from the disks 26, 27. The governor is rotated at such times, but the speed is insufficient to cause it to act upon the brake device 25. At the conclusion of each lifting movement, the pressure is reapplied to the lock, which automatically sustains the load at the new height. Slippage' in the device at these times practically does not occur, because-the load does not gather momentum, and when the load is at rest it is rigidly sustained beyond all possibilty of sinking, the looking or holding action being the greater, the greater the load. In order to lower the load, the operator moves the handle 83 so as to expand the brake 31 away fromthe drum 30 and thereby release the lock, which now permits the holding and lowering shaft 20, and therefore the entire mechanism, to run down. In this operation the'brake lock can be thrown off entirely, as the governor will assume control, exerting pressure upon the pile of disks 25 so as tov create such friction therein as to restrain the descending loaded ram to a safe speed. At any desired point the load is stopped by manually restoring the lock,

which can be done quickly, without injury;

the disks 26, 27 slipping sufliciently to soften the stopping as the automatic speed-controlled brake surrenders control.

The combinationbroadly of a speed-controlled brake in self-lowering jack mechanism is disclosed in theHindman Patent No. 1,234,334 of July 24, 1917, and is claimed herein in the novel construction and combinations more particularly pointed out in the appended claims.

hat is claimed as new is:

l; A self-lowering jack having an inclosing base frame provided with a standard, a ram vertically guided in said standard, a quick-pitch screw rotatably supported on the base and extending upward within the ram, a. horizontal lifting shaft in the'base frame geared to the screw, and a worm-wheel on said lifting-shaft, in combination with a shaft ournaled vertically in the base frame, a worm on said vertical shaft meshed by said worm-wheel and adapted to be driven thereby, a'manually releasable friction lock on the shaft subject to the end-thrust of the worm, and a speed-controlled brake device also on the vertical axis.

2. A self-lowering ack having an inclosing base frame provided with a-standard, a ram vertically guided in said standard, a quick-pitch screw rotatably supported on the base and extending upward within the ram, a horizontal lifting shaft in the base frame geared to the screw, and a worm-wheel on said lifting shaft, in combination with a shaft ournaled vertically in the base frame, worm on said vertical shaft meshed by said worrn-wheel and adapted to be driven thereby, two multiple friction disk devices on the vertical axis of said shaft, one of said devices being subject to the end-thrust of the load, manual means cooperating with said device, and a governor coacting with the other device to constitute a speed-controlled brake.

8. A self-lowering jack having an inclosing base frame provided with a' standard, a ram vertically guided in said standard, a quick-pitch screw rotatably supported on the base and extending upward within the ram, a horizontal lifting shaft in the base frame geared to the screw, and a worm-wheel on said lifting shaft, in combination with a shaft journaled vertically in the base frame, a worm on said vertical shaft meshed by said worm-wheel and adapted to be driven thereby, a manually controlled multiple friction disk lock on the shaft above the worm, a shelf in the inclosing frame against the under side of which said device is compacted by the upward end-thrust of the worm under load, a multiple friction disk brake over the shelf, and a governor on the upper part of the axis of the shaft adapted to compact the brake disks against the upper side of the shelf.

4. A self-lowering closing ard and an annex, a ram vertically guided in said standard, a quick-pitch screw rotatably supported on the base and extending upward within the ram, a horizontal lifting shaft in the annex of the base geared to the screw, and a worm-wheel on said shaft, in combination with a shaft journaled vertically in the annex, a worm on the lower part of said shaft meshing the worm-wheel and adapted to be driven thereby, a shelf in the annex through which the shaft passes, a multiple friction-disk lock on the vertical shaft between the worm and shelf to 'receive the upward end-thrust of the worm under load, a multiple friction disk brake resting on top of the shelf comprising members alternately anchored thereto and rotatable with the shaft, and a governor on the upper part of the shaft adapted to bear downwardly on the pile of brake disks.

5. In a self-lowering ack, having a jacking member and lifting mechanism adapted to run down under the load, a quick-pitch worm in driven relation to said mechanism, two multiple friction disk devices on V the axis of the worm, one being an automatic lock subject to the end-thrust of the worm and having manual means for releasing and restoring it, and the other being unaffected by such thrust, and a governor coacting with the second multiple friction disk device.

6. In a self-lowering jack, having a jacking member and lifting mechanism adapted to run down under the load, a quick-pitch worm in driven relation to said mechanism, two multiple friction disk devices on the axis of the worm, one being an automatic lock subject to the end-thrust of the worm jack comprising an inbase frame provided with a stand' and having manualmeans for releasing and restoring it, a governor coacting with the sccnrd multiple friction. disk device. the endthrust of the worm and the pressure of the governor being in opposite directions, and an abut-ment' between the multiple-disk devices.

'7. In a self-lowering jack, having a jacking member and lifting mechanism adapted to run down under the load, a quick-pitch worm and shaft in driven relation to said mechanism, two groups of friction disks on the shaft, one group being subject to the end thrust of the worm and comprising members alternately engaged with the shaft and free therefrom, a rotatable barrel with which such free disks are engaged, a hand brake acting upon said barrel, the other group of disks comprising members alternately engaged with the shaft and anchored against rotation, a fixed anchorage for the latter disks and fixed end abutment means for the two groups of disks, and a governor on. the shaft to act upon the second group of disks.

8. In a self-lowering jack, lifting mechanism comprising a steep-pitch screw and means for rotating the same, a shaft having a steep-pitch worm thereon, and a Wormwheel connected with the lifting mechanism for driving the Worm, combined with a manually-releasable friction lock automatically actuated by the end-thrust of the worm when the worm-wheel tends to turn the same under the action of the load seekingto descend, and an automatic speed controlled brake rotatable by said shaft in both directions and operative in the lowering direction to check the descent when the lock is released.

9. A self-lowering jack, comprising a jacking member and lifting mechanism adapted to run down under the load, and a wormwheel connected with said mechanism, in combination with mechanism on a single axis comprising a steep-pitch worm meshed by said worm-wheel, a friction lock subject to the end-thrust of the worm, manual means for releasing and restoring the lock, and a speed-controlled brake.

10. In a selfrlowering jack comprising a jacking member and lifting mechanism adapted to run down under the load, and a worm-wheel connected with said mechanism, the combination of a shaft having a worm adapted to be driven by said worm-wheel, an automatic speed-controlled brake device actuated by said shaft, a manually operated brake device, and cushion slippage means subject to the end-thrust of the worm, through which said manually operated brake device acts to arrest the descent of the loaded jacking member as the automatic brake device surrenders control.

- 11. In a self-lowering jack comprising a jacking member and lifting mechanism adapted to run down under the load, and a worm-wheel connected with said mechanism, an endwise movable shaft, a worm fast thereon adapted to be driven by said wormwheel, a friction lock on the shaft subject to the endthrust of the worm, manually operated means for controlling said lock, and a speedcontrolled brake fastened to another portion of the endwise movable shaft.

12. In a self-lowering jack having a lifting screw adapted to be rotated by the load, the combination of a lifting shaft geared to the screw, a worm-wheel on said shaft a second shaft having a worm to be driven by said worm-wheel, two multiple friction disk devices coaxial with the worm, manual means cooperating with one of said devices, and a governor operative upon the other multiple disk device.

13. In a self-lowering screw jack, and in combination with the lifting mechanism thereof, an auxiliary shaft in driven relation to the lifting mechanism, a multiple disk device comprising members alternately engaged with the shaft and held against rotation, and a speed governor for compacting the disks.

JOHN C. KOPF. 

